Normal Form Theorem for Logic Programs with Cardinality Constraints

Abstract

We discuss proof schemes, a kind of context-dependent proofs for logic
programs. We show usefullness of these constructs both in the context of
normal logic programs and their generalizations due to Niemela and
collaborators. As an application we show the following result. For every
cardinality-constraint logic program P there is a logic program PÃ‚Â´ with the
same heads, but with bodies consisting of atoms and negated atoms such
that P and PÃ‚Â´ have same stable models. It is worth noting that another
proof of same result can be obtained from the results by Lifschitz and
collaborators.